Near field detection is the ability to detect the presence of a mobile device or an individual carrying the mobile device from a short distance. Limiting near field detection to a range that is less than two feet may improve detection accuracy, and more specifically, the ability to detect a particular mobile device that is closest to a specific point of interest from other nearby mobile devices.
Mobile devices, such as smartphones, may have several different wireless radios, antennas, or integrated circuits for wireless communications using different wireless technologies. Each wireless technology may be associated with a different range. 4G Long Term Evolution (“LTE”) and WiFi are considered to be long range wireless technologies. Bluetooth and Near Field Communication (“NFC”) are considered to be short range wireless technologies.
Despite being considered a short range wireless technology, Bluetooth has a range of several feet which makes it an unreliable and an inaccurate wireless technology for near field detection. For example, a Bluetooth transmitter may be discoverable by any Bluetooth enabled device that is within several feet of the Bluetooth transmitter. The Bluetooth transmitter may be unable to accurately determine, without lengthy message exchanges, which of the Bluetooth enabled devices is closest to the Bluetooth transmitter, or has an established connection with the Bluetooth transmitter.
NFC has an operating range of a few inches (e.g., up to 6 inches), and is therefore well suited for near field detection. However, not all mobile devices include an NFC chip. Some mobile devices that include an NFC chip restrict third-party access to the chip or limit its usage.